FLOWERING PLANTS FOR LATE SUMMER/AUTUMN COLOUR

In most countries, spring and early summer are the normal flowering times for the majority of plants and for good reason too. How else would they be able to fit the time in to produce their fruiting bodies and seeds in time for autumn? Why autumn, well many of the seeds from cooler, temperate regions require a dormancy period before germination can occur. This dormancy period is usually broken by a period of cold weather, followed by warmer, wetter weather ensuring that germination occurs at the most suitable time. This enables the juvenile plants to make use of the longer warmer days for effective photosynthesis and gives them an entire year to grow, store energy as carbohydrates, and prepare for the following onset of winter.

Unfortunately this natural cycle of growth, flowering and seed production means that - for the ornamental gardener - gardens look a little worse for wear once the summer comes to an end, but with a little investigation there are plants from warmer climates that are ‘tricked’ into flowering at the wrong time of the year. This is because plants from warmer regions need certain triggers in order to initiate flowering. This can be day length, average day temperatures, average night temperatures, seasonal rainfall, light intensity, the list goes on. In cooler regions many of these triggers occur much later on in the year which is why there warmer climate plants flower later in cooler climates. Unfortunately they tend not to be able to produce fruiting bodies or viable seed before the colder temperatures of winter arrive. This can make it more difficult for propagation but for most gardeners this isn't a factor when they come to choose their late summer/autumn flowering plants.Below is a list of some of the best late summer/autumn flowering plants.

ANNUALS

Gazanias – this is an easy choice. Not only are they drought tolerant but they just keep on flowering – so long as the sun is out. All you need to do is remove the old flowers and periodically feed them with a liquid or water soluble fertilizer.

Mesembryanthemum – same as the above, flowering from June to September. Again, all you need to do is remove the old flowers and periodically feed them with a liquid or water soluble fertilizer.

Nicotiana – this plant species contains a large group of colourful cultivated varieties ideal for use in bedding schemes. However do not over look the tall gracefulness of the dramatic Nicotiana silvestris. Ideal for the boarders and in flower from June to October.

PERENNIALS

Agapanthus – a stunning plant from South Africa ranging in colour from pure white to the deepest blue, a must for any garden. Although some species can flower as early as late spring try to keep to A. Praecox and its hybrids which – in Northern Europe – will flower form July until August or September. Perhaps the best known are the popular Headbourne hybrids.

Canna lilies – These highly attractive plants are fantastic for bringing a touch of the tropic to the garden. Exotic flower are borne from July and can last up until November or at least until the first frosts arrive. Popular cultivars include the impressive ‘Lucifer and Tropicanna’.

Crocosmia species - Yet another exotic looking group of late flowering plants from South Africa. There are a number of very popular colour variations within this family notably 'Lucifer' and 'Emily McKenzie'. They will survive all but the most severe winters so long as they are planted in a well drained soil and are also excellent as cut flowers.

Dahlias - A good traditional choice that is coming back into fashion. Easy to grow and although considered to be half hardy can often overwinter if given extra protection and kept on the dry side.

Helianthus - the sun flower. Although these are a familiar sight during the main part of the summer the species H. Salicifolius will flower far later in September and October.
Helenium autumnale – As the name suggests this hardy perennial will flower from August through to October. Its cultivars come in a range of colours from a sunlight yellow to a burned red. Easy to grow for a stunning effect.

Hemerocallis – sneaking in just at the end of summer, Day Lilies give a fantastic show in a range of stunning colours.

Phlox paniculata – A superb late flowering, and easy to grow specimen boarder plant. Although its white form is perhaps the most striking there are plenty of good colour variations available.

Rudbeckia – A striking plant that has gained huge popularity in recent years. There are a large number of suitable specimens and cultivars within this family almost all of which are easy to grow and are even suitable for cut flower arrangements.

Verbascum - This contains a large family of plants many of which are reliable show stoppers, adding height, structure and a profusion of colour to summer borders. Popular varieties include V. ‘Gainsborough’, and V. ‘Cotswold Cream’ but there are many new varieties coming onto the market. Flowering lasts for up to three months from early to late summer - June to August in northern Europe.

BULBS/CORMS Colchicums – Commonly known as the Autumn Crocus or Naked Ladies – because they come into flower without leaves – colchicums can give a fantastic display from September to October. Although colchicums look like crocuses, they are actually members of the lily family. The most popular is C. 'Waterlily', and is perhaps the most common of all colchicums whose double pink blooms wouldn't look out of place floating on a pond. Raised almost a hundred years ago in a Dutch nursery, this variety is free-flowering and extremely easy to grow – often already flowering in the bag when purchased. There are a number of forms available but keep an eye out for C. agrippinum as it is one of the most distinctive. If you take closer look at its flower you will find that overlaying its pale pink petals is a deeper checkering like the pattern found on snake's head fritillaries.

Cyclamen – there are a number of good alpine cyclamen available such as C. Coum, C. hederifolium and C. Neopolitan but with our milder winters it is possible to successfully overwinter the more floriferous bedding species such as Cyclamen persicum which – if allowed to harden off – can apparently tolerate temperatures down to -7 degrees Celsius, but they must be grown in a free draining soil.

Schizostylis coccinea 'Major' – These eye-catching kaffir lilies provide a well needed late splash of colour when many of the summer flowers are coming to an end. Best planted in full sun, they are also perfect for a sheltered, moist but well-drained border. They also make excellent cut flowers.